1. Field of the Invention
This invention relates generally to electrical switching devices and more particularly, it relates to an improved appliance switch which includes a unique seal configuration for mating a base housing and a cover member so as to produce a watertight pushbutton switch.
In view of the increased public awareness for consumer safety in recent years, there has arisen the need of modifying or redesigning of many electrical appliances used in the household so as to prevent consumers from being accidentally electrocuted when such appliances were inadvertently short-circuited with water. As a result, a need has developed for an improved switching device which can be readily used in connection with such electrical appliances but can be operated in the presence of splashing water without creating an electrical hazard.
Although various aplications of the present invention will be readily apparent, the invention is especially useful in conjuction with a washing machine for controlling the motor thereof which requires an effective sealing of the contact switch externally so that it can perform reliably even in the presence of splashing water.
2. Description of the Prior Art
A prior art search directed to the subject matter of this application in the U.S. Patent and Trademark Office revealed the following U.S. Letters Patent:
______________________________________ 4,652,706 3,049,603 3,478,857 4,501,936 3,049,602 3,305,660 4,438,300 2,854,536 3,296,404 4,436,965 2,409,483 3,238,344 Re.29,047 2,343,060 3,042,764 3,932,722 4,555,600 2,812,402 3,372,246 4,298,778 2,790,881 3,317,698 4,184,321 2,750,480 3,316,379 4,021,630 2,451,176 3,246,112 3,790,734 2,394,271 3,054,879 3,737,605 2,213,649 ______________________________________
U.S. Pat. Nos. 4,652,706 to Rao et al.; 2,343,060 to Horning; 3,932,722 to Obata et al.; 3,246,112 to Adams et al.; 3,049,603 to Flatt et al.; 3,049,602 to Flatt et al.; 3,317,698 to Mansfield; and 3,054,879 to Soreng disclose switch mechanisms which include one-piece members defining a cover portion, a rolling or flexible seal portion, and an actuator means. U.S. Pat. Nos. 2,854,536 to Beer; 3,790,734 to Raab et al.; and 3,737,605 to Tobey et al. teach generally rolling seals and bellow type seals. The remaining patents uncovered from the search merely teach various integral elastomeric actuators and seals for attachment to a cover or housing and are thus considered to be only of general interest.
However, none of the prior art uncovered in the search disclosed an appliance switch having a base housing and a cover member like that of the present invention which includes a pair of cylindrically-shaped members formed on the interior of the cover member and being received snugly within respective pairs of trough-like recesses formed in the base housing so as to provide a stabilized engagement. Further, a rolling-type seal consisting of an inverted U-shaped flange is formed on the outer surface of the cover member for creating a tighter sealing contact between the cylindrically-shaped members and the trough-like recesses during the period of switch actuation.